Various problems present themselves in design of current inkjet printers, Modem inkjet printers print at very high resolution, for example, 600 or even 1200 dots-per-inch (DPI). As resolution in s droplet size typically decreases. With increased resolution and decreased dot size, it becomes more important that the pens be precisely located in the carriage. To accomplish accurate positioning of the pen in the carriage, the pen typically has a set of physical X, Y, and Z datums that are seated against a corresponding set of datums in the carriage stall.
Modem inkjet printers typically print in color and have a plurality of color pens, usually printing in cyan, magenta, yellow, and black. It is often desirable to provide a different pen for each color, so that if a single pen goes bad, only that pen need be replaced. However, each pen must be precisely aligned with the other colors, or the print quality of the printed images will be degraded. Therefore, the system must not only accommodate precision placement of the pens in the stalls, but precise alignment among the colors.
In addition to the mechanical positioning of the pens within the carriage, the pens must be fluidically connected to trailing tubes. The pens usually interface with some type of valve on the ends of the tubes. The pens make connection with these valves when they are inserted into the carriage stall. However, if the pen and valve interface is not correctly designed, the forces exerted on the pen during fluid interconnection will counteract the precision positioning of the datums, resulting in the pens being misaligned. The fluid interconnection mechanism must be designed so as to not act against the precise positioning resulting from the interaction of the datums.
Recent advances in printhead construction have allowed printheads to be designed to be a permanent or semi-permanent part of the printer, with separate ink cartridges that are fluidically connected in some fashion to the printhead.
Although the pens are preferably a permanent fixture in the printer, rather than being disposable, it is likely that many such pens will fail before the end of the life of the printer. Therefore, some provision must be made so that the pen can be removed and replaced with a new one. The mechanical datum system and fluid interconnect must also allow the new pen to be reliably and precisely positioned during such replacement. The system would be preferably designed so that installation and subsequent replacements could be done by a purchaser or by a field repair person away from factory conditions.